Air motor



Jan. 12, 1937. c. HARRIS-ET AL AIR MOTOR Original Filed July 2'7, 1931 2 Sheets-Sheet 1 Jan. 12, 1937. c. HARRIS Er AL AIR MOTOR Original Filed July 27, 1931 2 Sheets-Sheet 2 ///Vw/// VVWVW V a ||I mvsmon! ATTORNEYS Patented Jan. 12, 1937 UNITED STATES ace-1.63s

PATENT-.0

AIR MOTOR Cleo Harris and Clyde Ohio, assignors to The Company, Ohio Original application July 553,297, now Patent No.

this application August 25,

G. Butler, Cincinnati, Cincinnati Ball Crank Cincinnati, Ohio, a corporation cl 2'), 1931. Serial No. 1,981,507. Dividedand 1933, Serial No.

5 Claims. (Cl. 121-164) This invention relates to air motors and is particularly directed to an air motor of the type incorporating an automatically actuated reversing valve for constant reciprocation of a piston. This application is divisional of application Serial Number 553,297 flled July 27, 1931 by Cleo Harris 'and Clyde G. Butler now Patent Number l,981,- 507 issued July 20, 1934. As disclosed in the original case, the air motor is applied to the pumping piston of the grease pump. I

The mechanism for operating or changing the position of the air inlet and exhaust valve is controlled by the movement of the piston so that after a predetermined stroke of the piston in either direction the valve is tripped and the air supply and exhaust connections are alternately made to the cylinder for continuous reciprocation.

It is an object of this invention to provide an improved air motor of the continuously operating type in which a reversing valve is included, which valve is actuated by the piston at predetermined positions of its movement and is operated by an improved automatically tripped mechanism, whereby by the air motor cannot stall and the reversal of the piston occurs positively and accurately for uniformity and regularity of stroke. 7

It is a further object to improve the structure of the valve exhaust seat, whereby the constant engagement of the valve with the seat does not unduly wear the seat, and at the same time the seat is of a yieldable material for insuring a positive seal.

It is a further object of this invention to provide an improved arrangement of the air inlet relative to the control valve, whereby the valve is held against the particular seat through the medium of the air, this applying to both the inlet and outlet valves. This is a valuable improvement in that the air serves as an auxiliary means for holding the valve in closed position even when the valve operating mechanism may be efiective for this purpose.

. It is a further object of this invention to provide a valve operating mechanism which imparts a snap action to the valve for a minimum amount of time and a positive seal in the transfer of the valve from one seat to the other so that the reversal of the air flow is accomplished substantially incidentally with the time the piston has moved the prescribed amount.

Other objects and further advantages will be more fully apparent from a description of the acompanying drawings, in which: v

Figure 1 is a general view of a portable transfer pump incorporating the improved air motor, showing the pump mounted relative to an original container, the original container being Figure 5 is an enlarged diagrammatic view showing the relation of the valve, valve seats,

and stem for the purpose of accomplishing an unbalanced condition.

The air motor construction of this invention, as stated, has been illustrated in conjunction with the portable grease pump of the character disclosed in the original application.

The portable grease pump is of slender char- 2o acter so as to be conveniently and easily inserted into the standard commercial grease container through the average opening and for this purpose includes a generally coaxial arrangement of the major parts. A pumping cylinder is L secured on the lower end of a long discharge tube 2!, fixed at its upper end to the casing 22 01' an air motor unit 23, which air motor casing houses the air control mechanisms for the motor. A pumping piston 24 is located at the lower end of the discharge tube operating within the pump cylinder and is in operative contact with the piston 25 of the air motor through the discharge tube, by means of a piston rod 26.

This pump unit is depended into the original container 21 through the opening 28 thereof and is adjustably sustained by means of a closure and suppo device 29. The container 21 illustrated is of the conventional drum type. The closure and support device 29 includes a circular closure plate 30 having a circular depending flange 3| and adapted to fit over the top of the container with the flange 3| fitting over the edge thereof. This plate ,has a central aperture 32 extended upwardly by means of a split sleeve 33 designed to encircle the tube and to be slidable thereon.

The split portion'of the sleeve is traversed by a draw bolt 34 which may be tightened to set the closure and support device 29 in place when the tube has been adjusted to the depth of the particular tank or container for entirely or sub- 'stantially emptying the container of grease.

The grease drum or container opening is thus entirely closed to prevent the entrance of dirt into the grease. The closure plate '30 is secured in place by means of a plurality of hook bolts 35 depending through openings 36 and adapted to be hooked under the depending flange 3-! about 0 view taken on line the opening of the container and tightened by means of wing nuts 38 screwed. into their upper ends. The openings through which the hook piston rod 26. The pumping piston 24 is assembled on the lower end of the piston rod by means of a headed sleeve 49 screwed into the bore of the piston rod at the lower end thereof and securing oppositely turned gaskets 4| of the piston against the lower end of the piston,rod,.these gaskets being spaced by means of a washer 42.

The headed sleeve'includes an upwardly disposed valve seat 45 and has a ball valve 44 engaged against the seat, as formed by a converging bore wall at the lower end of the sleeve 40. The ball is preferably held against the seat by means of a coil spring 45 under compression between the ball and the upper end of the bore' of the piston rod. As will be apparent the spring compresses and the valve opens to downward stroke of the pumping piston. The grease passes through the tubular lower end of the piston rod and is'discharged upwardly and outwardly through a port or ports 46 extending from the interior of the hollow piston rod into the tube 2| above the pumping cylinder for discharge upwardly through the tube.

The piston rod 26. is slidably mounted at its lower end within the central bore of a tube closure cap or coupling 41 which is threaded into the lower end of the tube and provides the bored intermediate wall for guiding the piston rod. This element 41 also functions as a coupling device whereby the pumping cylinder 20 is screwed thereon. This closure cap or coupling means also serves for maintaining the piston return spring 48 in position of compression within the tube. The piston return spring 48 is maintained under adjustable compression downwardly against the closure cap by means of a nut- 49 screwed onto the piston rod and an inverted thimble 50 is inserted at the lower end of the tube, the thimble fitting snugly within the tube and resting upon the shoulder provided by the inserted upper end of the assembly sleeve, the fitting at this point being by means of a counterturnedl portion 5| on the thimble fitting over the inserted end of the sleeve. A cotter pin 52. maintains the nut 49 in set position. v

A gasket 54 is held between ment or cap 41 and the thimble and is enga ed about the piston rod at the point where it traverses the coupling element or cap 41 for sealing the sliding rod at this point. Since the thimble 59 surrounds the piston rod at the point of grease discharge outlet 46 of the hollowrod, the thimble includes outlet ports 53 in its upper end for permitting flow of grease directly into the tube.

For the purpose of preventing the vacuum which would occur at the top of the piston 24 within the pumping cylinder 29, a series of radially disposed apertures 55 are provided through the pump cylinder wall permitting the grease to enter above the piston.

By the arangement of parts described at the the coupling ele-' base of the gun; it will be apparent that the assembly of the pump at this point is extremely efllcient. v

With the piston rod in place within the tube, the piston return spring 48 is inserted against the nut 49v and the thimble 69 and gasket are placed upon the coupling sleeve or closure cap 41, the

coupling sleeve or cap 41 thereupon being screwed v 4 into the lower end of the tube thereby compressin the return spring into position whereupon it is conveniently possible to attach the parts of thepiston 24 to the rod 26 and to screw the pumping cylinder 29:.into p'osition about the pump piston.

An inlet valve-'|9 is. provided for. the pumping cylinder at its extreme lower end which valve is adapted to open on upstroke or intake stroke of the piston andto closeon downstroke or discharge cylinder head section 51, which slidably mounts the piston rod 26 and into which the tube 2| is screwed, and the upper cylinder head section 58 including a casing which houses the air motor control valves andoperating mechanism. .The

lower head 51 has a discharge passageway 59 disposed radially from the bore 69, into which the tube 2| is screwed. A meter 6| for measuring the discharge of the. pump is screwed into this pasageway and a flexible hose 62 extends from the meter. ,The hose is of sufficient lengthfor carrying the discharge tothepoint of service. A suitable valve mechanism and'manual control 63 is .includedat the outer end of the discharge hose for controlled delivery of the grease. The valve and control are not illustrated in detail herein since this apparatus forms the subject matter of a separate invention.

The piston rod 26 is sectional including two sections which are pivotally joined. The lower end of the upper section 64 is bifurcated and theend of the lower section 65 extends into the bifurcations and is pivotally secured in place therein by means of a cross pin 66. A packing gland 61 is screwed into the head 51 for sealing the sliding rod within the head.

The piston rod is made sectional for receiving the nut 49 one screw-threaded portion thereof,

the lower section being counterturned over its major portion with-the exception of its lower slidably mounted end. The piston section 64 and The piston rod assembly 26 extends into the air motor cylinder and the air motor piston 25 engages against its upper end. The air motor piston includes a. pair of discs 66 screwed together upon a gasket 69 which engages the walls of the cylinder and is disposed upwardly for action of the air thereagainst from above. The elements of the piston are clamped upon the head of the piston rod 16 for the air motor piston which extends upwardly through the upper disc and is slidably mounted through the upper. cylinder head 58. A packing gland 1| is provided at the point where the piston rod I0 traverses the cylinder head 58 for sealing the cylinder at this point.

The air is supplied to the air motor 23 through a pipe 52 extending from the main supply conduit i3, this pipe I2 connecting to the upper end of the air motor casing. A valve I4 is mounted in the passagewayl5 to which the pipe 72 connects- This passageway I5 extends from the valve downwardly through the upper cylinder head and enters the air motor cylinder above the piston. The opening and closing of the valve is automatically controlled "by the movement of the air motor piston through its piston rod I0 which actuates a toggle mechanism, the toggle mechanism acting upon the stem I6 of the valve 14 which stem is slidably mounted within the casing in the position parallel to the piston rod 10.

The valve stem I6 has a screw-threaded counterturned upper end upon which is screwed the valve element. The valve element I4 is held against the shoulder formed by the countertum by means'of a sleeve nut 'I'I scre wed onto the threaded portion from above. Two valve seat elements are provided, one I8 above and the other I9 below the valve element, the lower one functioning to cut off the air supply during the exhaust stroke of the air motor and the upper one functioning to cut off the exhaust when the supply is taking place.

The lower valve seat I9- is disposed within the lowerend of a bore in the casing which houses the valve assembly and includes suitable packing 80 engaged about the valve stem;

The bore within the lower valve seat element through which the valve stem passes, provides ample clearance for the passage of air, the air entering this bore through radial apertures 82 and a circumferential groove 83 which is supplied from the radially extended air supply passageway I5.

The upper valve seat element is spaced'from the lower valve seat element by means of a spacer sleeve 84 encircling the valve element I4 and providing ample clearance I for movement of the valve thereof and air passage. The upper valve seat element includes a flange 85 resting upon the upper end of the casing about the bore and a central bore clearing the valve assembly to permit air exhaust upwardly from the valve chamber.

The valve seats 18,19 and the spacer sleeve'Bl are held in position of assembly by means of an acorn nut 81 screwed onto the casing and upon the flange 85 of the upper valve seat. This nut includes a series of radially disposed exhaust ports 88. Packing 89 is provided under the respective heads of the valve seat elements where they abut the casing. The valve is adapted to move between the opposing and spaced seats thus provided, the seats proper being provided in both instances by circular bosses or raised portions on the respective elements.

In the instance of the upper valve seat to prevent undue wear of the seat and to provide a positive seal when the air is being supplied to the air motor, the seat combines metal and leather, rubber or some yieldable composition. For this reason a circular or annular lip 90 is extended from the valve seat element anda washer 9| equal in thickness to the height of the lip is disposed around the same and engaged against the under side of the valve seat element. Thus, when the valve I4 engages this seat, the contact with the metal and the leather is simultaneous. Great durability and a positive seal for the valve are thus provided.

The intermediate or spacer sleeve 84 is radially ported as at 92 and is grooved medially exterlorly as at 93 to provide passage for the air which passage communicates with the main air passageway ,15 to the air motor cylinder. The movement of the air motor piston rod I0 is efl'ective for actuating the valve controlling toggle mechanism and for this purpose is counterturned intermediate its length to provide up.- posing shoulders 94, 94, which shoulders are adapted to alternately engage the toggle.

The toggle elements are engaged to provide a knuckle adjacent the piston rod I0. The respective links 95, 96 of the toggle are pivotally mounted at their outer ends, one of the pivotal mountings being floating and yleldable to permit forced movement of the toggle past dead center and under spring pressure to provide pressure for snapping of the toggle past dead center. The toggle link 95 which has a fixed pivot 95 is of U-shape, straddling the valve,stem, and has the rounded ends 91 of its arms engaged in sem'icircular grooves formed in offset portions dis-5 posed intermediate of the length of the other toggle link 96.

The other toggle link comprises arms respectively disposed at opposite sides of the piston rod I0. The rounded inner ends 98 of the arms of the link .iIi are disposed between the arms of the first mentioned toggle link 95 and the outer ends are pivotally mounted on a pivot pin 99 disposed within the swinging end of a pivot bracket link I00 which is pivoted at its lower end in the casing on a pin I00. The swinging bracket I00 includes a pair of side arms and a cross plate IN. The cross plate portion is engaged by one end of a coil spring I02 under compression extending outwardly through a hollow boss I03 of the casing and maintained in position of compression by means of a plug I04 screwed onto the casing.

Under the action of the compression spring I02, the links 95, 96 of the toggle are maintained either in upper or lower position, past dead center, with the rounded swinging ends 99 of the toggle links 96 actively engaged against either an upper shoulder I05 or a lower shoulder I 06 of the valve stem formed by a counterturned portion in the same.

The toggle is designed to act rapidly under the action of the spring. When the air motor piston is at its upper position as shown in Figure 4,- the lower shoulder 94 of the piston rod I0 is engaging the toggle links, having forced the same past dead center toward that side, and the swinging ends 98 of the toggle links 96 having engaged the upper shoulder I05 on the valve stem thereby moving the valve into seated position on its upper seat to permit supply of air-above the piston and a power stroke thereof.

As the power stroke takes place, the piston moves downwardly under the action of the compressed air moving a distance which is governed by the distance between the shoulders 94, 94 of the piston rod until the upper shoulder 94 of the piston rod engages the toggle at the knuckle thereof. wardly forces the toggle by contact therewith at the point of the-knuckle downwardly to dead center compressing the spring I02 and storing up energy therein for a quick valve actuation. The moment the toggle passes dead center, the spring I02 under compression rapidly forces the toggle to the opposite side.- This swings the swinging ends 98 of the link parts 96 against the lower The power piston continuing down-.

spring 48 acts from below.

shoulder "it of the valve stemv and delivers a quick blow thereto which rapidly moves the valve to the lower seat thereby cutting off the air supply and permitting exhaust'through the supply passageway from above the piston as the return It will be observed that the opening and closing of the valve on either side is accomplished.

7 is snapped open.

It is provided that the'air under pressure is effective for holding the valve in its respective seat positions, particularly while the toggle is travelling between the shoulders Hi5 and I06, and until the time when the toggle has snapped past dead center and actuated the valve. After this occurrence the valve is held in seated'position under the action of the toggle spring, and the auxiliary force of the air under pressure would be unnecessary although it still continues to be effective. This result is. brought about by providing an unbalanced condition at the valve.

The relative diameters of the valve, stem, and passageway are important and are carefully determined for'this purpose. Referring to Figure 5, it will be noted that the valve diameter indicated at A is greater than the largest diameter B of the valve stem within the air inlet chamber insuringpositive seating of the valve against the exhaust seat. In the exhaust position the valve is held against the inlet seat because of the fact that the diameter of' the passageway indi!- cated at C between the air inlet chamber and the valve chamber is less than the largest diameter B of the valve stem within the air inlet chamber. v

The lower region of the air motor cylinder below the piston 25 is open to the atmosphere through a pipe I01 screwed into the lower end of the cylinder through the cylinder head and depending into the tank through an opening I08 in the closure means. of a-vacuum in the cylinder and permits the retu n to the tank of any grease escaping into the Y cylinder from the grease discharge tube.

' inder, an air supply conduit means connected to the cylinder of said air motor, a valve in said- Having described our invention, we claim:

1. An air motor, comprising, a piston and cylconduit means, said valve including a stem, said air motor piston including a rod, and a valve control toggle having its knuckle directly engaged by said piston rod, one of the arms of said toggle extended beyond the knuckle and acting on said valve stem for alternate admission of air into the motor cylinder and exhaust therefor, said valve stem and piston rod disposed between the pivots of said toggle, said valve control toggle arranged for delivering snap action to the valve stem at the limits of stroke of the piston for rapid opening and closing thereof. a

2. An air motor, comprising, a. piston and cylinder, an air supply conduit means connected to' the cylinder 'of said air motor, a valve in said conduit means, said valve including a stem, said air motor piston including a rod, a valve control This prevents formation toggle mechanism having -its knuckle directly engaged by said piston rod for movement past dead center, said toggle having one of its arms extended beyond the'knuckle and in position at each side of dead center engaging said valve 'stem for opening and closing said valve foralterlimits of stroke of the piston.

, 3. An air motor, comprising, a'piston and cylinder, an airsupply nduit means connected to the cylinder of said air motor, opposing valve seats in said supply conduit means, a valve in including a stem'having opposing shoulders; said air motor piston including ar'od having opposing shoulders, a valve control toggle having its knuckle disposed for alternate engagement by the shoulders of said piston rod, said valve stem and piston rod disposed between the pivots of the toggle, a spring for normally maintaining said toggle in either of saidpositions of alternate engagement, and said toggle having one of its arms extended beyond the knuckle and adapted to alternately engage the opposing shoulders of said valve stem whereby as the toggle is moved through dead center by pistonrod movement, the spring acts to deliver a snap action to the toggle for reversing the position of the valve on its seats at the limits of stroke of the air motor piston. v

4. An-air motor, including a cylinder and a piston, an air supply passageway for said cylinder, opposing inlet and exhaust control seats in sa d passageway, (a valve operative between said seats, said valve vincluding a stem; said piswith the shoulders of said valve stem, a-swinging plvot for one of the toggle arms, a spring for imparting pressure against the swinging pivot to normally maintain the toggle arms out of alignment whereby'alternate engagement of the knuckle by the respective shoulders and piston rod moves the toggle past dead center and causes the'sp ng to imparta snap action alternately moving the said inner arm end against the shoulders of the valve stem for actuation of the valve. v 5. An air motor including a piston and a cylinder, comprising, a valve casing providing a chamber, a conduit extending from said valve chamber to said cylinder, an exhaust'conduit extending from said valve chamber, a supply conduit extending to said valve chamber, a valve in said chamber including a stem, valve seats between the inlet conduit and the valve chamber and between the valve chamber and the exhaust conduit respectively, said valve stem slidably mounted through the inlet conduit and said valve having a diameter greater than the largest diameter of the stem within the inlet conduit, and the largest diameter of the stem being greater than the diameter of the passageway -from the inlet, conduit to the valve chamber.

CLEO HAIR IS. CLYDE G. BUTLER.

' ton including a piston rod disposed parallel to said stem, said stem-and piston rod respectively 

